1. Preheat oven to 350 degree.
2. Line 12-cup muffin tray with paper liners. Keep it aside.
3. In a large bowl, sift flour, cocoa, baking soda, and salt. Keep is aside.
4. In a separate bowl, combine canola oil and sugar. Whisk with electric mixer over medium speed for 2 minutes.
5. Add egg and beat for 3 minutes or until mixture thickens and becomes pale yellow in colour.
6. In a small bowl, put buttermilk, 1 teaspoon vanilla, food colour, and vinegar.
7. Pour colour mixture and flour alternatively into the bowl with egg and canola oil. Reduce mixer speed to low and blend to incorporate.
8. Pour batter evenly into muffin tray. Place it in the middle rack of the oven and bake for about 20 minutes or until toothpick comes out clean when inserted.
9. Transfer cupcakes on wire rack, and allow it to cool completely.
10. For icing, in a bowl, combine cream cheese, butter, and remaining vanilla. Beat until creamy.
11. Gradually add icing sugar to it. Whisk until completely blended.
12. Spread cream cheese frosting over cupcakes.
13. Using colourful piping gel, decorate cupcake as shown in the video.
14. Serve cupcakes immediately.
You may store iced cupcakes in an airtight container for up to 3 days.